You know the feeling of having your omega-3 capsule stick to the walls of your esophagus and lodge there until you drink more water or eat a piece of breath to shove it down? An object’s progress from mouth to stomach is an intricate dance of body position and muscle function. Now that you have been able to ruminate about chewing (See Part One: Chewing if you missed it), it’s time to move on to swallowing and how our habitual head position changes the reflex.
Remember, the digestive tract is a tube of smooth muscle that travels from the mouth to anus. Movement through most of the canal is achieved through peristalsis, or wave-like contractions of the tube walls. Skeletal muscles assist in areas of the tract where food needs to be propelled, like swallowing in the throat.
The skeletal muscles of swallowing are the geniohyoid, mylohyoid, and stylohyoid, collectively known as the suprahyoids. They form a sling of muscles along the underside of the jaw. They span from the anterior, inner edge of the mandible to the hyoid bone. The hyoid bone is a horseshoe shaped bone that floats between the root of the tongue and cartilage of the voice box. Their roles are to depress the mandible and to elevate the hyoid and tongue for swallowing.
Normal swallowing is a complex voluntary and reflexive process involving the tongue and sequential contraction of these muscles. Swallowing happens in four stages. As we chew our food, our tongue moves it around our mouth so it can be crushed and mixed with saliva. This forms a bolus, or round bundle of food ready for swallowing. In the first phase of swallowing, the tongue pushes the food mash toward the back of our throat. This is followed by the propulsion of the food into the upper pharynx through further contraction of the tongue. In the third stage, the bolus is transported through the pharynx and esophageal sphincter by synchronized muscular contraction of the suprahyoid muscles. Their action pulls the hyoid bone and voice box up and forward to open the entrance to the esophagus.
Our optimal swallowing mechanics are increasingly thrown off balance by habitual head thrusting known as forward head posture. Forward head posture has become more prominent due to the rise of smartphones and prevalence of computer usage. It is characterized by increased flexion of the lower cervical and upper thoracic regions, increased extension of the occiput on the first cervical vertebra, and increased extension of the upper cervical vertebrae. As a result, the head protrudes anterior to the trunk. Always jutting the head forward results in adaptive changes to muscles to compensate for the weight of the head against gravity. The trapezius, splenius capitis, splenius cervicis, and suboccipital muscles lengthen.
Additionally, forward head position displaces the normal alignment of the hyoid and mandible bones, where the suprahyoid bones attach. The constant thrusting of the head lengthens the suprahyoid muscles. Since proper functioning of the suprahyoid muscles is crucial in order to open the gateway to the esophagus, forward head posture can negatively influence swallowing mechanics and leave you with the feeling of food stuck in your throat.
The good news is this can be addressed with a few simple and effective Yoga Tune Up® exercises. Take computer and smartphone breaks through your day to ungunk your neck. Restore elasticity in the neck muscles with the Suboccipital Traction and Still Point Inducer ball rolling sequences. Strengthen the muscles to hold your head in alignment with your spine with Block Head.
Reverse forward head position while you’re eating too. With your head up, bring your utensils or hand toward your mouth instead of pushing your head forward to meet your food. Set your fork down between bites. Realign your head while chewing and then swallow to optimize suprahyoid muscle functions. That way you will ensure a smooth start to your digestion.
Stay tuned for the next installment of how muscle imbalances affect digestion. We will explore the abdomen and how habitual body positioning in the torso can slow the flow.